Voltage dropped

[TheReturnOfHightower]

So after what I thought was a productive day yesterday replacing old lights with LED panels, 3 of them weren't working. Turns out the voltage between line and neutral was about 210 at each of the 3 points, 245 between line and cpc. Voltage was 245 between line and neutral at all other points on the circuit.

I'm testing it coming Monday, but just racking my brain about it. The only thing I can think of is an insulation breakdown somewhere, either cables or in the click connectors. First test is naturally going to be IR, but thought I'd ask to see if anyone had any other ideas too so I can try it all Monday. Don't mind a bit of fault finding but man do I not have time for it at the moment.

 

[telectrix]

can't be an insulation break. seems more like a poor connection on the neutral at the first non-working light or the one before it. check connections in the click connectors.

 

[TheReturnOfHightower]

Why can't it be insulation degraded dropping some voltage across like a resistor? I've checked all connections (3 click connectors where the lights aren't working and also the next light upstream) - all seem solid. On Monday I was going to remove connections from all the clicks and reterminate temporarily in wagos to test again.

 

[James]

Poor joint in cable or at a fitting would be by best guess, put a temporary cable from 1 st not working to last working light.
210v would be enough to start most led lamps, if there is a break in the cable then that voltage could just be tracking across a cable break or bad joint.
Voltage could be dropping to near zero for short durations when the driver tries to start.

 

[GBDamo]

If these are the end of a line then the issue lies at the point of failure may be worth disconecting the drivers for each of the low voltage pannels form mains and testing the voltages.

Think its going to be fairly simple find with a fresh head on monday.

 

[telectrix]

Why can't it be insulation degraded dropping some voltage across like a resistor? I've checked all connections (3 click connectors where the lights aren't working and also the next light upstream) - all seem solid. On Monday I was going to remove connections from all the clicks and reterminate temporarily in wagos to test again.

you mean like leakage N-E? i would have thought that that would trip RCD (assuming there is one on the circuit).

 

[TheReturnOfHightower]

No RCD tel, but why can't current leak line to neutral through a breakdown in insulation. Not a dead short, but enough to drop voltage across?

All lights that weren't working were disconnected for testing the voltage. Think my plan is quick IR test, then after that I'm just going to rewire it as haven't got time to be messing about

 

[telectrix]

try dissing the first non-working light, but leaving the other 2 connected. could be a faulty fitting. I had 2 out of 24 duff out of the box on a recent job. 1 went pop on connecting, and the other flickerd on when hit with a large screwdriver handle ( an old trick from when TVs had valves inside. )

 

[TheReturnOfHightower]

I will, but with all 4 (3 non-working and last working one in the line) disconnected voltage was still around 210 at all 3 non-working points

 

[telectrix]

it's an intriguing one. let us know the outcome once you get it sorted.